New Caledonian carbon sinks at the onset of Antarctic glaciation

During the latest Eocene, as Earth's climate transitioned from a greenhouse to an icehouse state, likely forced by declining atmospheric carbon dioxide pressure (pCO(2)), a large tract of basic and ultrabasic seafloor breached sea level in the New Caledonian region of the southwestern Pacific Ocean. A plausible mechanism for CO2 drawdown at this precise time, 35-34 Ma, invokes weathering of the seafloor rocks, composed of highly soluble Ca- and Mg-rich silicates, and related organic carbon burial. Carbon burial fluxes based on estimates of paleo-area, paleo-erosion rate, and paleo-sedimentation rate suggest a peak perturbation of 0.3-0.5 Emol (10(18) mol) m.y(.-1) This perturbation may have been sufficient to lower atmospheric pCO(2) similar to 100 ppmv, thus triggering growth of the East Antarctic ice sheet and a host of related environmental changes.